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		</style><hr><a name="_C_FIELDPLOT"><div style="background-color:yellow;font-family:courier new;"></a>CLASS <b>FieldPlot</b> EXTENDS <a href="Plot .html#_C_PLOT " style="font-face:arial;font-weight:bold;">Plot </a></div>
<i>(Defined in: jpgraph_scatter.php : 63)</i><table border=1><tr><td>&nbsp;<a href="FieldPlot.html" style="font-family:arial;font-weight:bold;color:darkblue;">FieldPlot</a>&nbsp;</td><td>&nbsp;<a href="Plot .html" style="font-family:arial;font-weight:bold;color:darkblue;">Plot </a>&nbsp;</td></tr><tr><td valign=top>&nbsp;<a href="FieldPlot.html#_FIELDPLOT_FIELDPLOT">FieldPlot()</a>&nbsp;<br>
&nbsp;<a href="FieldPlot.html#_FIELDPLOT_SETCALLBACK">SetCallback()</a>&nbsp;<br>
</td><td valign=top>&nbsp;</td></tr></table>&nbsp;<p><div style="font-weight:bold;font-family:arial;font-size:100%;">Class usage and Overview</div>A variant of scatter plot is the so called <i>Field Plots</i> this is
basically a scatter plot where each scatter point is an arrow with a
direction between 0 to 359 degrees. This effectively allows the
visualization of 3 parameters at each point (x,y,angle). As an
additional bonus there is also possible to define a callback for each
scatter plot to also define the color for each point. <p> &nbsp;
<div style="font-weight:bold;font-family:arial;font-size:85%;">See also related classes:</div><a href="FieldArrow.html">FieldArrow</a> <p> &nbsp;<hr><span style="font-family:arial;font-size:120%;font-weight:bold;">Class Methods</span><hr><p>
<p>&nbsp; <p> &nbsp; <span style='font-size:110%;'><a name="_FIELDPLOT_FIELDPLOT"><div style="border-top:solid black 2pt;background-color:lightblue;font-family:courier new;font-size:90%;font-weight:bold;"><b><font color="#000000">
function&nbsp;FieldPlot($datay,$datax,$angles)</font>
</b></div></a></span>

<span style='font-family:arial;font-size:90%;'><i>Create an instance of FieldPlot</i></span><p>

<table cellspacing=0 style='border:black solid 1pt;' width=100%>
<tr><th width=25%>Argument</th><th width=15%>Default</th><th width=60%>Description</th></tr>
<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$datay</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>Y-coordinate</td></tr>

<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$datax</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>X-coordinate</td></tr>

<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$angles</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>Angle</td></tr>
</table>

<div style="font-weight:bold;font-family:arial;font-size:85%;">Description</div>Create a new instance of a field plot&nbsp;<br>

<div style="font-weight:bold;font-family:arial;font-size:85%;"><p>Example</div><span style="font-family:courier;font-size:85%;"><font color="#000000">
$fp&nbsp;=&nbsp;new&nbsp;FieldPlot($datay,$datax,$angle);</font>
</span><br>
<p>
<p>&nbsp; <p> &nbsp; <span style='font-size:110%;'><a name="_FIELDPLOT_SETCALLBACK"><div style="border-top:solid black 2pt;background-color:lightblue;font-family:courier new;font-size:90%;font-weight:bold;"><b><font color="#000000">
function&nbsp;SetCallback($aFunc)</font>
</b></div></a></span>

<span style='font-family:arial;font-size:90%;'><i>Specify callback for each arrow in the field plot</i></span><p>

<table cellspacing=0 style='border:black solid 1pt;' width=100%>
<tr><th width=25%>Argument</th><th width=15%>Default</th><th width=60%>Description</th></tr>
<tr><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'><font color="#000000">
$aFunc</font>

</td><td style='border-right:black solid 1pt;font-family:courier;font-size:90%;font-weight:bold;'>&nbsp;</td><td>Function name</td></tr>
</table>

<div style="font-weight:bold;font-family:arial;font-size:85%;">Description</div>Specify a callback that gets clled for each arrow in the field plot 
The callback should return an array with the elements
<ol>
<li> Color
<li> Size of arrow (in pixels)
<li> Arrow head size (as integer between0 and 9)
</ol>
&nbsp;<br>

<div style="font-weight:bold;font-family:arial;font-size:85%;"><p>Example</div><span style="font-family:courier;font-size:85%;"><font color="#000000">
//&nbsp;Gradient.&nbsp;Make&nbsp;the&nbsp;arrows&nbsp;red&nbsp;at&nbsp;the&nbsp;pole&nbsp;and&nbsp;colder&nbsp;(blue)
<br />//&nbsp;teh&nbsp;further&nbsp;we&nbsp;get&nbsp;from&nbsp;the&nbsp;pole
<br />function&nbsp;FldCallback($x,$y,$a)&nbsp;{
<br />&nbsp;&nbsp;&nbsp;&nbsp;$polex=4;
<br />&nbsp;&nbsp;&nbsp;&nbsp;$poley=40;
<br />&nbsp;&nbsp;&nbsp;&nbsp;$maxr&nbsp;=&nbsp;3000;
<br />
<br />&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;Size&nbsp;and&nbsp;arrow&nbsp;size&nbsp;is&nbsp;constant
<br />&nbsp;&nbsp;&nbsp;&nbsp;$size="";
<br />&nbsp;&nbsp;&nbsp;&nbsp;$arrowsize="";
<br />
<br />&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;Since&nbsp;we&nbsp;have&nbsp;different&nbsp;scales&nbsp;we&nbsp;need&nbsp;the&nbsp;data&nbsp;points
<br />&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;to&nbsp;be&nbsp;of&nbsp;the&nbsp;same&nbsp;magnitude&nbsp;to&nbsp;give&nbsp;it&nbsp;a&nbsp;distance
<br />&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;interpretation.
<br />&nbsp;&nbsp;&nbsp;&nbsp;$x&nbsp;*=&nbsp;10;&nbsp;
<br />
<br />&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;Colors&nbsp;gets&nbsp;colder&nbsp;the&nbsp;further&nbsp;out&nbsp;we&nbsp;go&nbsp;from&nbsp;the&nbsp;center
<br />&nbsp;&nbsp;&nbsp;&nbsp;$r&nbsp;=&nbsp;($x-$polex*10)*($x-$polex*10)+($y-$poley)*($y-$poley);
<br />&nbsp;&nbsp;&nbsp;&nbsp;$f&nbsp;=&nbsp;$r/$maxr;
<br />&nbsp;&nbsp;&nbsp;&nbsp;if(&nbsp;$f&nbsp;&gt;&nbsp;1&nbsp;)&nbsp;$f=1;
<br />&nbsp;&nbsp;&nbsp;&nbsp;$red&nbsp;=&nbsp;floor((1-$f)*255);
<br />&nbsp;&nbsp;&nbsp;&nbsp;$blue&nbsp;=&nbsp;floor($f*255);
<br />&nbsp;&nbsp;&nbsp;&nbsp;$color&nbsp;=&nbsp;array($red,0,$blue);
<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;array($color,$size,$arrowsize);
<br />}
<br />
<br />//&nbsp;Setup&nbsp;the&nbsp;field&nbsp;plot
<br />$fp&nbsp;=&nbsp;new&nbsp;FieldPlot($datay,$datax,$angle);
<br />
<br />//&nbsp;Setup&nbsp;formatting&nbsp;callback
<br />$fp-&gt;SetCallback('FldCallback');</font>
</span><br>
<p> <hr> <p>